Cross-Correlated Interface Research Unit

Principal Investigator

PI Name Pu Yu
Degree Ph.D.
Title Unit Leader
Brief Resume
2011Ph.D. in Physics, University of California, Berkeley, USA
2012Postdoctoral Researcher, Correlated Electron Research Group, RIKEN, Japan
2012Assistant Professor, Tsinghua University, Beijing, China
2014Unit Leader, Cross-Correlated Interface Research Unit, Cross-Divisional Materials Research Program, RIKEN Center for Emergent Matter Science (-present)
2017Associate Professor, Tsinghua University, Beijing, China
2018Professor, Tsinghua University, Beijing, China (-present)


Our research unit is dedicated to exploring the emergent phenomena at complex oxide and other cross-correlated heterostructures and interfaces. In particular, we are interested about quantum manipulation of ferroelectric and ferromagnetic properties by means of heteroepitaxy, artificial design of novel multiferroic materials with strong magnetoelectric coupling and emergent phenomena (with a strong focus on the spin and charge degrees of freedom) at complex oxide interfaces and their cross correlations to other correlated material systems. Our goal is to reveal the underlying mechanisms of these heretofore-unexplored functionalities, and transfer them into novel device concepts for applications.

Research Fields

Condensed Matter Physics, Materials Sciences


Interface electronic structure
Magnetoelectric effect
Thin films and interfaces


Electric field control of ionic evolution: a novel strategy to redesign materials

The correlation between charge, spin, orbital and lattice degrees of freedom at complex oxides generates a wealth of exotic electronic states with promising applications. Conventionally, chemical substitution during the growth forms an essential pathway to manipulate the carrier density, leading to a rich spectrum of properties. To obtain a further control of the carrier density after growth, electrostatic charge modulation has been widely employed. However, an intrinsic limitation of this approach is that it is only effective for materials with thicknesses of a few nanometers, due to the short electrostatic screening length. Recently the electric-field induced ionic evolution demonstrates a great tunability in a series of bulk compounds. Among the studies, the hydrogen ion (proton) attracts particular attention due to its comparatively small radius as well as easy accessibility. The insertion of protons electron-dopes the materials, leading to an exotic electronic and magnetic phase transition along with the increase of proton concentration. We envision that electric-field controlled protonation opens a new avenue to systematically control the electronic and magnetic phase diagram in strongly correlated complex oxide systems.

Manipulation the coupling and correlation between degrees of freedom through ionic evolution.


Pu Yu

Unit Leader R